The present invention relates generally to integrated circuit designs, and more particularly to methods of storing data with electrical fuses for device mismatch and process variation trimming.
Device mismatch or process variation trimming is typically helpful in designing analog circuitry or logic circuitry with analog nature, such as sense amplifiers. The conventional approaches are either trimming on demand without keeping the trimming data or storing the trimmed data in non-volatile devices such as flash memory, Electrically Erasable Programmable Read Only Memory (EEPROM), or Erasable Programmable Read Only Memory (EPROM).
If trimming data are not saved and are generated on demand, it can consume large amount of time and power. Data can be saved in non-volatile devices such as flash memory or EEPROM, but they are not compatible with standard logic process. Such incompatibility results in a higher cost. Laser trimming, which is a computer-controlled material-removing technique by vaporization that is commonly used for trimming resistors, is another trimming method that is often used in analog-to-digital (A/D) or digital-to-analog (D/A) converters. Even though this method can provide precise narrow cuts and break specific laser fuses that can be used for storing information such as trimming data, the process can be rather expensive.
It is always desirable to have a simple and cost efficient solution to store trimming data to improve system accuracy.